Add latexmk.pdf to docs.
    Update to 4.30a:
    - Fix use of bibtex when $aux_dir and/or $out_dir are set.
    - Documentation of $search_path separator variable.
    - Work with feynmp package and mpost.
    - Let dvips find files in the output directory.
    - In search for cus-deps that can make a missing file, look in $out_dir.
    - Parse biber 0.9.7 error messages.